This application is based upon and claims the benefit of Japanese Patent Applications No. 2000-83918 filed on Mar. 24, 2000, No. 2000-214152 filed on Jul. 14, 2000, No. 2000-214204 filed on Jul. 14, 2000, No. 2000-214333 filed on Jul. 14, 2000, and No. 2000-214449 filed on Jul. 14, 2000, the contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a boiling cooler for cooling a heating element by heat transfer with boiling.
2. Description of the Related Art
JP-A-8-204075 discloses a boiling cooler that cools a heating element by heat transfer with boiling of refrigerant. This boiling cooler can provide a high thermal conductivity in comparison with air-cooling and water-cooling methods. Therefore, it is widely used as a cooler for a semiconductor device that generates a large heat flux. This boiling cooler is composed of a refrigerant tank for storing liquid refrigerant, a radiator for cooling vapor of refrigerant that is boiled in the refrigerant tank by heat generated from the heating element, and a cooling fan for supplying cooling air to the radiator.
In the conventional boiling cooler, however, while condensation heat transfer is performed with a large thermal conductivity at the inside of the radiator, cooling with air is performed with a smaller thermal conductivity at the outside of the radiator. Therefore, the size of the radiator must be increased to comply with the necessity for the cooling with air. As a result, the installation of the boiling cooler is liable to be limited. Especially when the boiling cooler is mounted on a vehicle or the like, its mountability is very low because it must be disposed in a narrow space.
The present invention has been made in view of the above problems. An object of the present invention is to provide a boiling cooler having good mountability.
According to the present invention, briefly, a boiling cooler has a heat exchange part in which refrigerant vapor performs heat exchange with liquid. The refrigerant vapor is produced from liquid refrigerant that is boiled and gasified by heat transferred from a heating element. In this boiling cooler, the refrigerant vapor can be cooled by the liquid (for example, water) having a thermal conductivity larger than that of air. Therefore, unlike the conventional cooler, a large-sized radiator is not required, and as a result, the size reduction of the boiling cooler can be realized, resulting in good mountability to a vehicle.